Rohde & Schwarz R&S UPP, User Manual

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Remote Control - Fundamentals
R&S
®
UPP
660 User Manual 1411.1055.32 ─ 10
6.6.6 Output Unit
The output unit collects the information requested by the controller and which it obtains
from database administration. It processes the information in line with SCPI rules and
makes it available in the output buffer.
If the device is addressed as a talker and the output buffer does not contain any data
or expect data from the database, the output unit sends the error message "Query
UNTERMINATED" to the status reporting system. No data are sent on the IEC/IEEE
bus or Ethernet, and the controller waits for the set time limit. This procedure is prescri-
bed by SCPI.
6.6.7 Triggering Measurement or Sweep
There are three ways of triggering a measurement or a sweep :
●
* By the SCPI-specific command
INIT
●
* By the common command
*TRG
●
* With the addressed command G roup E xecute T rigger
GET
All three possibilities are equivalent and similar in the time they take to execute.
There are also three ways of waiting for a triggered measurement result, which are
looked at in the next section. To demonstrate the three trigger possibilities together
with singly triggered measurement results, command synchronization with *WAI is
used in what follows.
6.6.8 Command Synchronization
To ensure that commands are executed in a certain sequence, one of the commands
*OPC, *OPC? or *WAI must be used. As a result of these commands, a certain action
is not triggered until the hardware is set and settled. The controller can be forced
through appropriate programming to wait for the appearance of an action.
Table 6-1: Synchronization with *OPC, *OPC? and *WAI
Command Effect Programming of controller
*OPC Sets the Operation Complete bit in the
ESR after processing all commands
sent before *OPC. - Set bit 0 in ESE
- Set bit 5 in STB
- Wait for Service Request
*OPC? Stops further command processing
until 1 is returned. This is not the case
until the Operation Complete bit is set
in the ESR. This bit indicates that the
previous setting has been completed. Send *OPC? directly after the com-
mand whose processing should be ter-
minated before other commands can be
executed.
*WAI Stops further command processing
until all commands sent before *WAI
have been executed. Send *WAI directly after the command
whose processing should be terminated
before other commands are executed.
Device Model and Command Processing